One answer to that question, he notes, may be found in a recent study from the British Journal of Psychology. It shows how easily people can be manipulated into believing one thing has caused another, even when it hasn’t.
These “illusions of causality,” says Goldacre, are much like visual illusions.
The study involved 108 student participants, who were divided into two groups. They were told about a made-up disease (“Lindsay Syndrome”) and a potential treatment for the disease, Batarim (also, of course, fictional). They were then read the individual “case reports,” one by one, of 100 patients with the syndrome. In the reports, some of the patients had received Batarim and some hadn’t.
In the case reports read to one of the groups of students, 80 patients had received the drug and 20 hadn’t. The reports read to the second group reversed those numbers: 20 of the patients had received the drug and 80 hadn’t.
But in both sets of case reports, 80 percent of the patients had gotten better, regardless of whether or not they had received Batarim.
When asked at the end of the case study readings about the effectiveness of Batarim at treating “Lindsay Syndrome,” however, the two groups had different opinions. Both groups overestimated the benefits of the drug, but particularly those in the first group.
Why? “One possibility,” says Goldacre, “is that the students in the second group saw more patients getting better without the treatment, and so got a better intuitive feel for the natural history of the condition, while [the students] who were told about 80 patients getting Batarim were barraged with data about people who took the drug and got better.”
“This is just the latest in a whole raft of research showing how we can be manipulated into believing that we have control over chance outcomes, simply by presenting information differently, or giving cues which imply that skill had a role to play. One series of studies has even shown that if you manipulate someone to make them feel powerful (by remembering a situation in which they were powerful, for example) then they imagine themselves to have even greater control over outcomes that are still purely determined by chance, which perhaps goes some way to explaining the hubris of the great and the good.
“We know about optical illusions, and we’re familiar with the ways that our eyes can be misled. It would be nice if we could also be wary of cognitive illusions that affect our reasoning apparatus, but more than that, like the ‘close door’ buttons in a lift — which, it turns out, are often connected to nothing at all — these illusions are modern curios.”
You can read Goldacre’s column here.